Cleaning device, method for detecting suction nozzle clogging, and automatic analyzer

ABSTRACT

A cleaning device includes a discharge nozzle that discharges cleaning liquid; a suction nozzle that sucks the cleaning liquid or reaction liquid in the cleaning tank or the reaction vessel; a discard vessel connected to the suction nozzle via a pipe to discard the cleaning liquid or the reaction liquid; a detecting unit that detects whether an electrostatic capacity at least between the suction nozzle and an electrode provided in the pipe exceeds a threshold value; a determination unit that determines that the suction nozzle is clogged when a totalizing time, for which the electrostatic capacity exceeds the threshold value during a preset clogging determination time, is longer than a totalizing time, for which the electrostatic capacity exceeds the threshold value during a preset normal determination time; and a control unit that stops the discharge nozzle from discharging the cleaning liquid to the reaction vessel when the suction nozzle is clogged.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of PCT international application Ser.No. PCT/JP2007/063032 filed on Jun. 28, 2007 which designates the UnitedStates, incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a cleaning device, a method fordetecting suction nozzle clogging, and an automatic analyzer.

2. Description of the Related Art

A conventional automatic analyzer includes a cleaning device that sucksreaction liquid, which is obtained through a reaction between a specimenand a reagent, from a reaction vessel and discharges cleaning liquidinto the reaction vessel to clean the reaction vessel (for example, seeJapanese Patent Application Laid-open No. 2000-266763). In such anautomatic analyzer, the cleaning device sucks the reaction liquid fromthe reaction vessel using a nozzle, and sometimes a foreign material inthe reaction liquid clogs the nozzle.

SUMMARY OF THE INVENTION

A cleaning device according to an aspect of the present inventionincludes a discharge nozzle that discharges cleaning liquid; a suctionnozzle that is inserted into a cleaning tank or a reaction vessel alongwith the discharge nozzle to suck the cleaning liquid or reaction liquidin the cleaning tank or the reaction vessel; a discard vessel that isconnected to the suction nozzle via a pipe to discard the cleaningliquid or the reaction liquid; a detecting unit that detects whether anelectrostatic capacity at least between the suction nozzle and anelectrode provided in a middle of the pipe exceeds a predeterminedthreshold value; a determination unit that determines that the suctionnozzle is clogged when a totalizing time, for which the electrostaticcapacity exceeds the predetermined threshold value during a presetclogging determination time, is longer than a totalizing time, for whichthe electrostatic capacity exceeds the predetermined threshold valueduring a preset normal determination time; and a control unit that stopsthe discharge nozzle from discharging the cleaning liquid to thereaction vessel when the determination unit determines that the suctionnozzle is clogged.

According to another aspect of the present invention, there is provideda method for detecting suction nozzle clogging in a cleaning devicehaving a discharge nozzle that discharges cleaning liquid, a suctionnozzle that is inserted into a cleaning tank or a reaction vessel alongwith the discharge nozzle to suck cleaning liquid or reaction liquid inthe cleaning tank or the reaction vessel, and a discard vessel that isconnected to the suction nozzle via a pipe to discard the cleaningliquid or the reaction liquid, the method including detecting whether anelectrostatic capacity at least between the suction nozzle and anelectrode provided in a middle of the pipe exceeds a predeterminedthreshold value; and determining that the suction nozzle is clogged whena totalizing time, for which the electrostatic capacity exceeds thepredetermined threshold value during a preset clogging determinationtime, is longer than a totalizing time, for which the electrostaticcapacity exceeds the predetermined threshold value during a presetnormal determination time.

According to still another aspect of the present invention, there isprovided an automatic analyzer that stirs a specimen and a reagent tocause a reaction, measures an optical characteristic of reaction liquid,and analyzes the reaction liquid, the automatic analyzer cleaning asuction nozzle that sucks cleaning liquid or the reaction liquid usingthe cleaning device

The above and other features, advantages and technical and industrialsignificance of this invention will be better understood by reading thefollowing detailed description of presently preferred embodiments of theinvention, when considered in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram illustrating the configuration of anautomatic analyzer according to an embodiment of the present invention;

FIG. 2 is a schematic explanation diagram illustrating the schematicconfiguration of a cleaning device;

FIG. 3 is a block diagram illustrating a detecting unit of the cleaningdevice;

FIG. 4 is a block diagram illustrating a determination control unit ofthe cleaning device;

FIG. 5 is a diagram illustrating an example of a time chart, in whichone cleaning period contains B/F cleaning in a reaction vessel andsuction-nozzle cleaning in a cleaning tank;

FIG. 6 is a schematic diagram illustrating the arrangement of a cleaningtank, a suction nozzle, a pipe, a detection electrode, and a reservoirand illustrating a state where B/F cleaning liquid is sucked between thesuction nozzle and the reservoir;

FIG. 7 is a diagram illustrating a state where the B/F cleaning liquidis further sucked from a position illustrated in FIG. 6, the leading endof the B/F cleaning liquid comes in contact with the detectionelectrode, and the suction nozzle and the detection electrode areconnected to each other;

FIG. 8 is a diagram illustrating a state where the sucked B/F cleaningliquid is further sucked from a position illustrated in FIG. 7 and theleading end of the B/F cleaning liquid moves to a position between thedetection electrode and the reservoir;

FIG. 9 is a diagram illustrating a state where the sucked B/F cleaningliquid is further sucked from a position illustrated in FIG. 8, theleading end of the B/F cleaning liquid comes in contact with theelectrode of the reservoir, and the detection electrode and theelectrode of the reservoir are connected to each other;

FIG. 10 is a diagram illustrating examples of a voltage variation, athreshold voltage, and a binarized waveform detected by the detectingunit on the basis of the change of electrostatic capacity caused bycleaning liquid flowing between the suction nozzle and the reservoirwhen the suction nozzle is not clogged;

FIG. 11 is a diagram illustrating examples of a voltage variation, athreshold voltage, and a binarized waveform detected by the detectingunit on the basis of the change of electrostatic capacity caused bycleaning liquid flowing between the suction nozzle and the reservoirwhen the suction nozzle is partially clogged;

FIG. 12 is a diagram illustrating examples of a voltage variation, athreshold voltage, and a binarized waveform detected by the detectingunit on the basis of the change of electrostatic capacity caused bycleaning liquid flowing between the suction nozzle and the reservoirwhen the suction nozzle is perfectly clogged;

FIG. 13 is a flowchart explaining a method for detecting suction nozzleclogging that is performed in the cleaning device;

FIG. 14 is a diagram illustrating examples of a voltage variation, athreshold voltage, and a binarized waveform detected by the detectingunit on the basis of the change of electrostatic capacity caused bycleaning liquid flowing between the suction nozzle and the detectionelectrode when the suction nozzle is not clogged; and

FIG. 15 is a diagram illustrating examples of a voltage variation, athreshold voltage, and a binarized waveform detected by the detectingunit on the basis of the change of electrostatic capacity in the sameinterval as that of FIG. 14 when the suction nozzle is partiallyclogged.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Exemplary embodiments of a cleaning device, a method for detectingsuction nozzle clogging, and an automatic analyzer will be describedbelow in detail with reference to the accompanying drawings. Anautomatic analyzer for immune analysis, to which the cleaning device andthe method for detecting suction nozzle clogging are applied, will bedescribed.

<Outline of Immune Analysis Process>

The outline of an immune analysis process performed by an automaticanalyzer according to an embodiment of the present invention isdescribed first. In the present embodiment, an immune measurement usinga heterogeneous reaction is performed. As an example, a case ofmeasuring the concentration of a predetermined antigen in a specimenusing an enzyme immunoassay (EIA) will be explained. In the immuneanalysis process, an immune reaction (antigen-antibody reaction) isfirst caused by mixing a specimen and a solid phase that is sensitizedby an antibody that specifically couples to a predetermined antigen inthe specimen. In the following description, a reaction vessel is appliedas a solid phase. It is assumed that a predetermined antibody ispreviously adsorbed in the vicinity of the inner-wall bottom surface ofthe reaction vessel.

After the immune reaction, reaction liquid within the reaction vessel issucked by a suction nozzle, B/F cleaning of the reaction vessel (pre-B/Fcleaning) is performed by predetermined B/F cleaning liquid dischargedfrom a discharge nozzle, and then an antibody or a specimen component(including an antigen), which is not specifically coupled to theantibody and is isolated from the antibody, is separated and removedfrom the solid phase. Then, the suction nozzle moves to a cleaning tankalong with the discharge nozzle to be cleaned. In the reaction vessel,chromogenic substrate, in which enzyme that is labeled substance showsactivity, is added. A chromogenic reaction is caused between labeledsubstance remaining in the reaction vessel and the chromogenicsubstrate. A chromogenic amount is optically measured. Then, an antigenconcentration in the specimen, which is an analysis target, is obtainedby performing a comparison between data obtained by the measurement anddata (calibration curve) obtained from a normal specimen of which theconcentration of an antigen is known.

Sometimes, operations of the immune reaction, B/F cleaning, and nozzlecleaning are performed plural times. Similarly to the above, theconcentration of a predetermined antibody in a specimen can be measured.In this case, an antigen that specifically couples to the antibody ispreviously adsorbed on a solid phase. An analysis of specimen can beperformed by applying an immunoassay method using a heterogeneousreaction other than an enzyme immunoassay described above. Such animmunoassay method includes a fluorescent immunoassay (FIA) that uses afluorescent substance as a labeled substance, a radioactive immunoassay(RIA) that uses a radioactive isotope as a labeled substance, a chemicalenzyme immunoassay (CLIA) that uses a chemiluminescent substrate as alabeled substance, and a spin reagent immunoassay (SIA) that uses a spinreagent as a labeled substance.

<Configuration of Automatic Analyzer and Cleaning Device>

FIG. 1 is a schematic diagram illustrating the main configuration of anautomatic analyzer according to an embodiment of the present invention.An automatic analyzer 1 includes a measurement system 2 and a controlanalysis system 40. The measurement system 2 dispenses a sample, such asa specimen, and a reagent to a reaction vessel and performs opticalmeasurement on liquid within the reaction vessel. The control analysissystem 40 performs driving control on the measurement system 2 andperforms an immunological analysis on a sample component based on themeasurement result performed by the measurement system 2. These twosystems cooperate to perform an immunological analysis on a plurality ofsample components automatically and continuously. The followingexplanation is made assuming that the automatic analyzer 1 performsimmunological measurement using a heterogeneous reaction.

As illustrated in FIG. 1, the measurement system 2 includes a specimentransferring unit 3, a carrier reagent table 5, a liquid reagent table6, a reaction table 7, a specimen dispensing unit 8, a carrier reagentdispensing unit 9, a liquid reagent dispensing unit 10, a stirring unit13, a photometry unit 14, and a cleaning device 20.

The specimen transferring unit 3 mounts thereon a plurality of racks 4,each of which holds specimen vessels 4 a for accommodating specimens,and sequentially transfers the plurality of racks 4. The carrier reagenttable 5 holds a plurality of carrier reagent vessels 5 a arranged in acircumferential direction and has a driving unit for rotating it in acircumferential direction. The carrier reagent vessel 5 a accommodates acarrier reagent that is used for an antigen-antibody reaction with aspecimen. The liquid reagent table 6 holds liquid reagent vessels 6 athat accommodate various types of liquid reagents. The liquid reagenttable 6 has a driving unit for rotating it in a circumferentialdirection, which is different from the driving unit of the carrierreagent table 5. The reaction table 7 holds reaction vessels 7 a, inwhich reactions between specimens and reagents are caused, and has adriving unit for rotating it in a circumferential direction similarly tothe carrier reagent table 5.

The temperature of each table is kept constant. For example, the liquidreagent table 6 is set to a temperature lower than a room temperature tosuppress the degradation and denaturation of a reagent. The reactiontable 7 is set to a temperature equal to a human body temperature.

The specimen dispensing unit 8 dispenses specimens accommodated in thespecimen vessels 4 a on the specimen transferring unit 3 to the reactionvessels 7 a held on the reaction table 7. The carrier reagent dispensingunit 9 dispenses carrier reagents accommodated in the carrier reagentvessels 5 a on the carrier reagent table 5 to the reaction vessels 7 a.The liquid reagent dispensing unit 10 dispenses liquid reagentsaccommodated in the liquid reagent vessels 6 a on the liquid reagenttable 6 to the reaction vessels 7 a.

The specimen vessel 4 a includes an information code recording medium(not shown) affixed thereto that records identification information foridentifying a specimen accommodated therein by coding the identificationinformation to an information code such as a bar-code or atwo-dimensional code. Similarly, the carrier reagent vessel 5 a and theliquid reagent vessel 6 a each include an information code recordingmedium (not shown) affixed thereto that records identificationinformation for identifying a reagent accommodated therein by coding theidentification information to an information code. The measurementsystem 2 includes an information code reading unit CR1 that reads aninformation code affixed to the specimen vessel 4 a, an information codereading unit CR2 that reads an information code affixed to the carrierreagent vessel 5 a, and an information code reading unit CR3 that readsan information code affixed to the liquid reagent vessel 6 a.

The specimen dispensing unit 8, the carrier reagent dispensing unit 9,and the liquid reagent dispensing unit 10 each include a canalicularprobe that performs the suction and discharge of a specimen, an arm thatmoves the probe up and down in a vertical direction and rotates theprobe in a horizontal direction, and a suction/discharge mechanism thatuses a suction/discharge syringe or the like. In order to preventcontamination and carry-over, a disposable method is employed. Aremovable chip is attached to the leading end of the probe. The chip isexchanged for each dispensing operation. The specimen dispensing unit 8includes, on an operation line thereof, a chip storing unit 8 a forstoring unused chips and a chip discarding unit 8 b for discarding usedchips.

A reaction vessel transferring unit 11 transfers the reaction vessel 7 ain order to place the reaction vessel 7 a on the reaction table 7 or toremove the reaction vessel 7 a from the reaction table 7. The reactionvessel transferring unit 11 includes, on an operation line thereof, areaction vessel storing unit 11 a for storing unused reaction vessels 7a and a reaction vessel discarding unit 11 b for discarding usedreaction vessels 7 a. The reaction vessel transferring unit 11 may haveany configuration as far as it transfers liquid without spilling theliquid in the reaction vessel 7 a.

The stirring unit 13 stirs liquid accommodated in the reaction vessel 7a. The photometry unit 14 includes a photomultiplier tube that measuresweak light emitted by reaction liquid within the reaction vessel 7 a. Incase of measuring fluorescent light that is generated from reactionliquid, the photometry unit 14 may be provided with a light source forirradiating exciting light.

The cleaning device 20 performs B/F cleaning of a carrier reagent andcleaning of a suction nozzle 21 b as illustrated in FIG. 2. The cleaningdevice 20 includes a plurality of B/F cleaning nozzle pairs 21A to 21F,each of which has as a pair a discharge nozzle 21 a that discharges B/Fcleaning liquid and the suction nozzle 21 b that sucks liquid. Thesuction nozzle 21 b is made of metal excellent in electricalconductivity, such as aluminum. The lower end of the suction nozzle 21 bis positioned lower than the lower end of the discharge nozzle 21 a.Each of the B/F cleaning nozzle pairs 21A to 21F is transferred to anozzle cleaning tank 30 every time B/F cleaning after an immune reactionin the reaction vessel 7 a is completed using a nozzle transferring unit22. The nozzle transferring unit 22 collectively moves vertically andhorizontally and rotates horizontally the B/F cleaning nozzle pairs 21Ato 21F. Then, the suction nozzle 21 b is cleaned by the B/F cleaningliquid discharged from the discharge nozzle 21 a. A control unit 45controls the vertical movement of the nozzle transferring unit 22 usinga top point at a position raised in a vertical direction as an originalpoint.

Because the nozzle transferring unit 22 collectively transfers the B/Fcleaning nozzle pairs 21A to 21F, relative position relationshipsbetween the discharge nozzle 21 a and the suction nozzle 21 b of thenozzle pairs are not changed before and after the transfer.Incidentally, the nozzle transferring unit 22 is capable of transferringthe nozzle pairs individually.

The discharge nozzles 21 a are connected to a syringe 24 via a commonpipe 23. The syringe 24 includes a cylinder 24 a and a piston 24 b. B/Fcleaning liquid LBF is introduced into the pipe 23 and the cylinder 24a. In the syringe 24, the operation of the piston 24 b is controlled bya piston driving unit 25 that is controlled by the control unit 45. Thesyringe 24 is connected to a cleaning liquid vessel 29 that accommodatesthe B/F cleaning liquid LBF via a pipe 26. An injection valve 27 thatcontrols the flow of the B/F cleaning liquid LBF and a pump 28 thatsucks the B/F cleaning liquid LBF from the cleaning liquid vessel 29 areprovided in the pipe 26. When the B/F cleaning liquid LBF is to beintroduced into the pipe 23 and the cylinder 24 a, the injection valve27 is opened, the B/F cleaning liquid LBF is filled up into thedischarge nozzle 21 a, the syringe 24, the pipes 23 and 26 using thepump 28, and then the injection valve 27 is closed to terminate theoperation of the pump 28.

Each of the suction nozzles 21 b of the B/F cleaning nozzle pairs 21A to21F is connected to a reservoir 33 via an individual pipe 31. Each ofthe suction nozzles 21 b is connected to a frame ground FG of theautomatic analyzer 1. Each of the pipes 31 has the same diameter betweenthe suction nozzle 21 b and the reservoir 33 and provided with adetection electrode 32 at a mid point between the suction nozzle 21 band the reservoir 33. The detection electrode 32 is provided at theposition such that an amount of the B/F cleaning liquid existing betweenthe suction nozzle 21 b and the detection electrode 32 is smaller thanan amount of the B/F cleaning liquid within the cleaning tank 30. Thedistance between the suction nozzle 21 b and the detection electrode 32is set to be equal to or shorter than the distance between the detectionelectrode 32 and a reservoir electrode 33 a.

The detection electrode 32 detects the change of electrostatic capacitycaused by the B/F cleaning liquid flowing through the pipe 31 betweenthe suction nozzle 21 b and the detection electrode 32 or between thedetection electrode 32 and the reservoir electrode 33 a of the reservoir33, and outputs an electrical signal corresponding to the change ofelectrostatic capacity to a detecting unit 36.

The reservoir 33 is connected to a vacuum pump, which causes negativepressure in the reservoir 33, via a pipe that has a suction valve 34.The reservoir 33 is provided with the reservoir electrodes 33 a atlocations to which the respective pipes 31 are connected. One end of thereservoir electrode 33 a is connected to the B/F cleaning liquid flowingthrough the pipe 31 and the other end is connected to the frame groundFG of the automatic analyzer 1. The reaction liquid sucked from thereaction vessel 7 a and the B/F cleaning liquid sucked from the nozzlecleaning tank 30 are discharged from the reservoir 33 to an externalwaste liquid tank 33 b through a pipe that has an exhaust valve 35.

The detecting unit 36 detects the change of electrostatic capacitybetween the suction nozzle 21 b and the reservoir electrode 33 a as abinarized waveform that is a difference relative to a threshold voltage.The detecting unit 36 is provided on a detection board 36 a for each ofthe B/F cleaning nozzle pairs 21A to 21F. As illustrated in FIG. 3, thedetecting unit 36 includes an oscillation circuit 36 b, an I-Vconverting unit 36 c, a filter 36 d, a DC converting unit 36 e, apeak-hold circuit 36 i, a differential amplifier 36 j, and a comparator36 k.

The I-V converting unit 36 c converts the change of electrostaticcapacity output from the detection electrode 32 provided in the pipe 31of the suction nozzle 21 b into the change of an alternating voltageusing an alternating current signal output from the oscillation circuit36 b. The filter 36 d is a bandpass filter that passes only a signalnear oscillating frequency oscillated by the oscillation circuit 36 band removes noises included in the change of alternating voltageconverted by the I-V converting unit 36 c. The DC converting unit 36 econverts voltage variation of alternating current signal into voltagevariation of direct current that has less ripples using a rectifyingdevice 36 f, a smoothing circuit 36 g, and a long pass filter 36 h.

The peak-hold circuit 36 i is a circuit that detects whether the B/Fcleaning liquid passes the detection electrode 32 with high precisionusing the change of electrostatic capacity relative to a reference ofelectrostatic capacity. The reference is an electrostatic capacity whenthe suction nozzle 21 b does not suck the B/F cleaning liquid. Thepeak-hold circuit 36 i holds a direct voltage before the electrostaticcapacity is changed as a reference voltage. In order to use a stableelectrostatic capacity as a reference, the peak-hold circuit 36 i resetsthe previous reference voltage saved in the peak-hold circuit 36 i ofeach of the detecting units 36 and holds the present new direct voltageas a reference voltage when the B/F cleaning liquid is discharged fromone of the discharge nozzles 21 a of the B/F cleaning nozzle pairs 21Ato 21F in the nozzle cleaning tank 30. At that time, the control unit 45that receives a signal output from the piston driving unit 25 inputs apeak-hold reset signal to the peak-hold circuit 36 i.

The differential amplifier 36 j outputs a voltage variation amountbetween the reference voltage held in the peak-hold circuit 36 i and thevoltage variation of the direct current converted by the DC convertingunit 36 e. The comparator 36 k compares the voltage variation amountinput from the differential amplifier 36 j with a threshold voltage setin a binarization threshold circuit 36 m and outputs a binarizedwaveform (see FIGS. 10 to 12, FIG. 14, and FIG. 15) that is a differencebetween the voltage variation amount and the threshold voltage to adetermination control unit 37 via a photo coupler 36 n. The binarizedthreshold value, i.e., the threshold voltage is set to an intermediatevalue between a voltage value when an electrostatic capacity caused bythe B/F cleaning liquid flowing through the pipe 31 is largest and avoltage value when the electrostatic capacity is smallest.

As illustrated in FIG. 4, the determination control unit 37 includes apeak-hold-reset output circuit 38 and determination units 39 that arerespectively provided for the B/F cleaning nozzle pairs 21A to 21F andrespectively determine whether the suction nozzles 21 b are clogged.

The peak-hold-reset output circuit 38 outputs a peak-hold reset signalto the peak-hold circuit 36 i of the detecting unit 36. Concerning thepeak-hold reset signal, a timing at which cleaning liquid is dischargedto the reaction vessel 7 a is extracted from a driving signal for thesyringe 24 and a driving signal for the B/F cleaning nozzle pairs 21A to21F that are output from the piston driving unit 25 and the nozzletransferring unit 22 and are input to the peak-hold-reset output circuit38 via the control unit 45. The peak-hold reset signal is pulse-shaped.

The determination unit 39 totalizes binarized waveforms input from thedetecting unit 36 and determines whether the suction nozzle 21 b isclogged. As illustrated in FIG. 4, the determination unit 39 includes anormal-determination-time setting circuit 39 a, aclogging-determination-time setting circuit 39 b, a first timer 39 e, asecond timer 39 f, and a comparing circuit 39 g.

The normal-determination-time setting circuit 39 a sets the startingpoint and ending point of a normal determination time based on adetermination start signal input from a storage unit 44 through an inputport 39 p and a set value 1 input through an input port 39 m, andoutputs the points to an AND circuit 39 c. The ending point of thenormal determination time is the starting point of a cloggingdetermination time. The AND circuit 39 c extracts ON components of abinarized waveform, which is input from the normal-determination-timesetting circuit 39 a, during the normal determination time and outputsthe ON components to the first timer 39 e.

The clogging-determination-time setting circuit 39 b sets the endingpoint of the clogging determination time based on a set value 2 inputfrom the storage unit 44 through an input port 39 n, and outputs thepoint to an AND circuit 39 d. The AND circuit 39 d extracts ONcomponents of a binarized waveform, which is input from theclogging-determination-time setting circuit 39 b, during the cloggingdetermination time and outputs the ON components to the second timer 39f.

The first timer 39 e totalizes the ON components of the binarizedwaveform, which is input from the AND circuit 39 c, during the normaldetermination time and outputs a totalizing time T1 to the comparingcircuit 39 g and an output port 39 h. The second timer 39 f totalizesthe ON components of the clogging determination time having a binarizedwaveform input from the AND circuit 39 d, and outputs a totalizing timeT2 to the comparing circuit 39 g and an output port 39 i.

The comparing circuit 39 g compares the totalizing time T1 and thetotalizing time T2 input from the first timer 39 e and the second timer39 f. The comparing circuit 39 g then determines that the suction nozzle21 b is clogged when the totalizing time T2 is not less than thetotalizing time T1 (T1≦T2) and outputs the determination to an outputport 39 j.

The totalizing time T1 output to the output port 39 h, the totalizingtime T2 output to the output port 39 i, and the determination result ofthe effect that the suction nozzle 21 b is clogged output to the outputport 39 j are output from the output ports to the storage unit 44. Areset signal read from the storage unit 44 by the control unit 45 isinput to an input port 39 k.

The detecting unit 36 and the determination control unit 37 areillustrated separately from the control unit 45 in FIG. 2. However, inorder to simplify the configuration, the automatic analyzer 1 of thepresent invention utilizes the control unit 45 as the detecting unit 36and the determination control unit 37 to be integrated with the controlunit 45.

In the cleaning device 20 having the above-described configuration andfunction, operations of the nozzle transferring unit 22, the pistondriving unit 25, the injection valve 27, the pump 28, the suction valve34, and the exhaust valve 35 are controlled by the control unit 45 ofthe control analysis system 40.

In the measurement system 2 having the above-described configuration, arotation angle of the reaction table 7 rotated by one rotation actuationis previously determined. All components are arranged so that dispensingof a specimen or various types of reagents can be performedsimultaneously and variously together with this rotation. Thus, FIG. 1is a diagram only schematically illustrating the components of themeasurement system 2. In other words, a mutual positional relationshipbetween the components of the measurement system 2 is a design matter tobe determined in accordance with a condition such as a rotation mode ofthe wheel of the reaction table 7.

The control analysis system 40 includes an analysis computing unit 41,an input unit 42, an output unit 43, the storage unit 44, and thecontrol unit 45.

The analysis computing unit 41 performs analysis calculation on themeasurement result obtained in the measurement system 2. The input unit42 inputs an actuation instruction signal of the automatic analyzer 1and information required for the analysis of a specimen. The input unit42 is realized by a keyboard, a mouse, a microphone, and the like. Theoutput unit 43 outputs information including an analysis result, and isrealized by a display (CRT, liquid crystal, plasma, organic EL, and thelike), a printer, a speaker, and the like.

The storage unit 44 stores therein information including various typesof parameters related to the automatic analyzer 1 or the cleaning device20 in addition to the analysis result. The storage unit 44 includes ahard disk that magnetically stores various information and a memory thatloads, when the automatic analyzer 1 and the cleaning device 20 performvarious types of processes, programs related to the processes from thehard disk and electrically records the programs. During initialization,the control unit 45 reads the set values 1 and 2 for setting the normaldetermination time and the clogging determination time, the resetsignal, and the determination start signal from the storage unit 44, andoutputs these signals to the determination control unit 37. The setvalues 1 and 2 are set at the time of maintenance of the automaticanalyzer 1 and are input to the storage unit 44.

The reset signal is a signal for resetting the totalizing time (T1)totalized by the first timer 39 e of the determination unit 39, thetotalizing time (T2) totalized by the second timer 39 f, and thedetermination result (T1≦T2) performed in the comparing circuit 39 g,and is input from the input port 39 k (see FIG. 4) to the determinationunit 39. The determination start signal is a signal for instructing thedetermination control unit 37 to start determination. The determinationstart signal is output from the control unit 45 to the determinationunit 39 during a period from a time, at which the discharge of the B/Fcleaning liquid from the discharge nozzle 21 a to the reaction vessel 7a has started in response to the start of drive of the piston drivingunit 25, to a time, at which the discharge nozzle 21 a and the suctionnozzle 21 b are transferred to the nozzle cleaning tank 30 by the nozzletransferring unit 22 and the B/F cleaning liquid is discharged to thenozzle cleaning tank 30 to start the nozzle cleaning.

The storage unit 44 may further include an auxiliary storage device thatcan read information recorded in a recording medium such as a flexibledisk, CD-ROM, DVD-ROM, a magnet-optical disk, a PC card, or an xDpicture card.

The control unit 45 controls the automatic analyzer 1 and reads aprogram stored in the storage unit 44 from the memory to performanalysis calculation using the measurement result in the measurementsystem 2, the control of various types of actuations of the automaticanalyzer 1, and the like.

When the control analysis system 40 having the above configurationreceives a photometric result of weak light emitted by reaction liquidfrom the photometry unit 14, the analysis computing unit 41 computes anamount of luminescence of the reaction liquid within the reaction vessel7 a and uses a calibration curve obtained from a normal specimen and ananalysis parameter included in the analysis information in addition tothe computation result in order to quantitatively calculate thecomponent of reaction liquid. The analysis result obtained in this wayis output from the output unit 43 and is further stored in the storageunit 44.

The cleaning device 20 of the present invention having the aboveconfiguration performs vertical movements and horizontal movements ofthe plurality of B/F cleaning nozzle pairs 21A to 21F using the nozzletransferring unit 22 so as to perform the B/F cleaning of the reactionvessel 7 a and internal/external cleaning of the suction nozzle 21 b inthe cleaning tank 30. An example of a time chart in which the B/Fcleaning in the reaction vessel 7 a and the cleaning of the suctionnozzle 21 b in the cleaning tank 30 are performed in one cleaning periodis illustrated in FIG. 5.

FIG. 5 is a time chart regarding the movement of the nozzle transferringunit 22 that transfers the discharge nozzle 21 a and the suction nozzle21 b of one of the B/F cleaning nozzle pairs, the discharge of the B/Fcleaning liquid performed by the discharge nozzle 21 a, the opening(nozzle cleaning with the sucking of the B/F cleaning liquid performedby the suction nozzle 21 b) of the suction valve 34 that causes negativepressure in the reservoir 33, and the opening of the exhaust valve 35that discharges liquid (reaction liquid and B/F cleaning liquid) withinthe reservoir 33. In FIG. 5, solid lines show a horizontal movement or avertical movement of one of the B/F cleaning nozzle pairs performed bythe nozzle transferring unit 22, the discharge of the B/F cleaningliquid from the discharge nozzle 21 a, and the opening of the suctionvalve 34 and the opening of the exhaust valve 35. Dotted lines show thatthe nozzle transferring unit 22 does not move. In FIG. 5, parts that donot have marks for the opening of the suction valve 34 and the exhaustvalve 35 indicate that the valves are closed.

As illustrated in FIG. 5, in the cleaning device 20, the nozzletransferring unit 22 moves the B/F cleaning nozzle pairs downward at theposition of the reaction vessel 7 a from 0 second to 0.5 second and thenstops the pairs at a bottom point from 0.5 second to 1.8 second, andthen moves the B/F cleaning nozzle pairs upward toward the top pointfrom 1.8 second to 2.2 second and stops the pairs. During that time, thesuction valve 34 is opened from 0 second to 0.4 second to causesnegative pressure in the reservoir 33, and the reaction liquid withinthe reaction vessel 7 a is sucked into the reservoir 33 by the suctionnozzle 21 b. The discharge nozzle 21 a discharges the B/F cleaningliquid into the reaction vessel 7 a from 0.7 second to 1.7 second toperform B/F cleaning on the inside of the reaction vessel 7 a. Theexhaust valve 35 is opened from 1.5 second to 2.0 second, the suckedreaction liquid is discharged from the reservoir 33, and the B/Fcleaning of the reaction vessel 7 a is completed. Because the suctionvalve 34 is opened from 2.0 second to 3.2 second and causes negativepressure in the reservoir 33, the suction nozzle 21 b sucks part of theB/F cleaning liquid within the reaction vessel 7 a while being movedupward by the nozzle transferring unit 22.

Subsequently, the nozzle transferring unit 22 horizontally moves the B/Fcleaning nozzle pairs from 2.2 second to 2.6 second from the position ofthe reaction vessel 7 a toward the position of the cleaning tank 30while keeping the pairs at the top point between 2.2 second and 2.7second. The pairs are kept at the position of the cleaning tank 30 up to5.8 second. The nozzle transferring unit 22 then horizontally moves theB/F cleaning nozzle pairs from 5.8 second to 6.2 second from theposition of the cleaning tank 30 toward the position of another reactionvessel 7 a and then stops the pairs between 6.2 second and 7.5 second.The nozzle transferring unit 22 moves the B/F cleaning nozzle pairsdownward from 2.7 second to 3.1 second and then stops the pairs at thebottom point at the position of the cleaning tank 30 between 3.1 secondand 5.4 second, and then moves the B/F cleaning nozzle pairs upward from5.4 second to 5.8 second and then stops the pairs at the top point. Thenozzle transferring unit 22 stops the B/F cleaning nozzle pairs at thetop point between 5.8 second and 6.3 second, and then moves the B/Fcleaning nozzle pairs downward from 6.3 second to 7.2 second and stopsthe pairs at the bottom point up to 7.5 second.

During that time, the discharge nozzle 21 a discharges the B/F cleaningliquid to the cleaning tank 30 from 3.1 second to 4.2 second. With this,the outside of the suction nozzle 21 b is cleaned. Also, the B/Fcleaning liquid just discharged from the discharge nozzle 21 a is suckedby the suction nozzle 21 b up to 3.2 second due to the attractive forceof the reservoir 33 that is in negative pressure between 2.0 second and3.2 second. The inside pressure of the reservoir 33 again becomesnegative by opening the suction valve 34 from 4.3 second to 5.0 second,and the B/F cleaning liquid within the cleaning tank 30 is sucked toclean the suction nozzle 21 b. Then, the suction valve 34 is opened from6.3 second to 7.2 second to cause negative pressure in the reservoir 33and sucks reaction liquid within another reaction vessel 7 a, towardwhich the move was made between 5.8 second and 6.2 second.

FIG. 5 illustrates a basic cleaning period of the cleaning device 20.The B/F cleaning of the reaction vessel 7 a and the internal/externalcleaning of the suction nozzle 21 b in the cleaning tank 30 can beperformed by changing times or combining a plurality of the cleaningperiod as needed.

The nozzle transferring unit 22 moves the plurality of B/F cleaningnozzle pairs 21A to 21F to the cleaning tank 30, and the suction nozzle21 b sucks the B/F cleaning liquid, which has discharged by thedischarge nozzle 21 a to the cleaning tank 30, from the cleaning tank30. Then, the B/F cleaning liquid within the cleaning tank 30 sucked bythe suction nozzle 21 b is discharged to the reservoir 33 through thepipe 31. In this way, the suction nozzle 21 b is cleaned by the suckedB/F cleaning liquid. When the suction nozzle 21 b sucks the B/F cleaningliquid from the cleaning tank 30, the B/F cleaning liquid LBF within thecleaning tank 30 is sucked into the pipe 31 as illustrated in FIG. 6. Asillustrated in FIG. 7, when the leading end of the B/F cleaning liquidLBF within the pipe 31 comes in contact with the detection electrode 32,the electrostatic capacity is largely changed due to the B/F cleaningliquid LBF between the suction nozzle 21 b and the detection electrode32.

The suction nozzle 21 b further sucks the B/F cleaning liquid LBF withinthe cleaning tank 30, and the electrostatic capacity becomes small whenthe leading end of the B/F cleaning liquid LBF within the pipe 31 haspassed the detection electrode 32 and the rear end of the B/F cleaningliquid LBF has also passed the suction nozzle 21 b as illustrated inFIG. 8. As illustrated in FIG. 9, when the leading end of the B/Fcleaning liquid LBF within the pipe 31 arrives at the reservoir 33 andthe rear end side of the B/F cleaning liquid LBF touches the detectionelectrode 32, an electrostatic capacity is largely changed again due tothe B/F cleaning liquid LBF between the detection electrode 32 and thereservoir electrode 33 a.

In the cleaning device 20, the detecting unit 36 detects the change ofelectrostatic capacity caused by the B/F cleaning liquid flowing throughthe pipe 31 as a binarized waveform that is a difference relative to athreshold voltage. FIG. 10 illustrates examples of a voltage variation,a threshold voltage, and a binarized waveform output from thedifferential amplifier 36 j of the detecting unit 36 based on the changeof electrostatic capacity when the suction nozzle 21 b is not cloggedwith foreign materials. The normal determination time and the cloggingdetermination time are also depicted. In FIG. 10, the binarized waveformhas ON states at two points. The first ON state is detected when theleading end of the B/F cleaning liquid LBF within the pipe 31 passes thedetection electrode 32 as illustrated in FIG. 7. The second ON state isdetected when the leading end of the B/F cleaning liquid LBF within thepipe 31 arrives at the reservoir 33 and the rear end side of the B/Fcleaning liquid LBF touches the detection electrode 32 as illustrated inFIG. 9. The time for which the binarized waveform has the ON state inthe normal determination time illustrated in FIG. 10 is totalized by thefirst timer 39 e of the determination unit 39 and is referred to as thetotalizing time T1. In FIG. 10, the normal determination time starts atzero second and its horizontal axis shows a time scale. This is similarin FIGS. 11 and 12. FIGS. 10 to 12 are diagrams when the pipe 31 is notclogged.

When the suction nozzle 21 b is partially clogged, the flow of the B/Fcleaning liquid within the pipe 31 becomes slow. FIG. 11 illustratesexamples of a voltage variation, a threshold voltage, and a binarizedwaveform output from the differential amplifier 36 j of the detectingunit 36 in the normal determination time and the clogging determinationtime is. As illustrated in FIG. 11, because the flow of the B/F cleaningliquid within the pipe 31 is slow, the binarized waveform becomes an ONstate in the clogging determination time after the termination of thenormal determination time. Therefore, the time difference (ΔT) is causedbetween the ON times of the binarized waveform illustrated in FIG. 11and the binarized waveform illustrated in FIG. 10. The time for thebinarized waveform becomes an ON state in the clogging determinationtime is totalized by the second timer 39 f of the determination unit 39as the totalizing time T2. When the suction nozzle 21 b is perfectlyclogged, because the suction nozzle 21 b cannot suck the B/F cleaningliquid, the B/F cleaning liquid does not flow through the pipe 31. FIG.12 illustrates examples of the voltage variation, the threshold voltage,and the binarized waveform output from the differential amplifier 36 jof the detecting unit 36 in the normal determination time and theclogging determination time.

In the method for detecting suction nozzle clogging according to thepresent invention, the change of electrostatic capacity caused by theB/F cleaning liquid flowing through the pipe 31 is detected as abinarized waveform, and the presence or absence of the clogging of thesuction nozzle 21 b is determined based on the totalizing times T1 andT2 of the binarized waveform in the normal determination time and theclogging determination time.

Hereinafter, the method for detecting suction nozzle clogging performedin the cleaning device 20 will be described with reference to theflowchart illustrated in FIG. 13.

First, when the electric source of the automatic analyzer 1 is turned onand the control unit 45 is initialized, the cleaning device 20determines whether nozzle cleaning in the cleaning tank 30 is started(Step S100). This determination is made using a signal that is inputfrom the piston driving unit 25, which causes the discharge nozzle 21 ato discharge the B/F cleaning liquid, to the control unit 45. As adetermination result, when the piston driving unit 25 does not operateand the B/F cleaning liquid is not discharged from the discharge nozzle21 a (Step S100: No), the determination of Step S100 is repeated.

When the piston driving unit 25 operates and the B/F cleaning liquid isdischarged from the discharge nozzle 21 a into the cleaning tank 30(Step S100: Yes), the cleaning device 20 determines whether adetermination start signal is input to the determination unit 39 of thedetermination control unit 37 (Step S102). This determination is madedepending on whether the control unit 45 outputs the determination startsignal that is read from the storage unit 44 to the determination unit39. When the determination start signal is not input to thedetermination unit 39 (Step S102: No), the cleaning device 20 terminatesthe clogging detection of the suction nozzle 21 b.

In contrast, when the determination start signal is input to thedetermination unit 39 (Step S102: Yes), the cleaning device 20 resetsthe totalizing times T1 and T2 (Step S104). The reset of the totalizingtimes T1 and T2 is performed by outputting the reset signal read fromthe storage unit 44 to the determination control unit 37 by the controlunit 45.

Subsequently, the cleaning device 20 opens the suction valve 34 (StepS106). The opening of the suction valve 34 is performed by outputting anopening signal to the suction valve 34 by the control unit 45. In thisway, negative pressure is caused in the reservoir 33, the B/F cleaningliquid within the cleaning tank 30 is sucked by the suction nozzle 21 b,and the suction nozzle 21 b is cleaned.

Subsequently, the cleaning device 20 detects the change of electrostaticcapacity caused by the B/F cleaning liquid flowing through the pipe 31as a binarized waveform (Step S108). The detection of the binarizedwaveform is executed by the detecting unit 36. After that, the cleaningdevice 20 counts the totalizing time T1 of the detected binarizedwaveform in the normal determination time (Step S110). The count of thetotalizing time T1 is executed by the determination unit 39 to which thebinarized waveform is input.

Then, the cleaning device 20 determines whether the normal determinationtime has passed (Step S112). This determination is made by thedetermination unit 39. When the normal determination time has not passed(Step S112: No), the cleaning device 20 returns the process control toStep S110 and repeats the count of the totalizing time T1. When thenormal determination time has passed (Step S112: Yes), the cleaningdevice 20 counts the totalizing time T2 of the detected binarizedwaveform in the clogging determination time (Step S114). The count ofthe totalizing time T2 is executed by the determination unit 39 to whichthe binarized waveform is input.

Next, the cleaning device 20 determines whether the cloggingdetermination time has passed (Step S116). This determination is made bythe determination unit 39. When the clogging determination time has notpassed (Step S116: No), the cleaning device 20 returns the processcontrol to Step S114 and repeats the count of the totalizing time T2.

When the clogging determination time has passed (Step S116: Yes), thecleaning device 20 determines whether the totalizing time T2 is not lessthan the totalizing time T1 (Step S118). This determination is executedby the comparing circuit 39 g of the determination unit 39. As adetermination result, when the totalizing time T2 is less than thetotalizing time T1, the B/F cleaning liquid flows through the pipe 31within the normal determination time and the suction nozzle 21 b is notclogged. Therefore, the cleaning device 20 terminates the cloggingdetection of the suction nozzle 21 b.

In contrast, when the totalizing time T2 is not less than the totalizingtime T1, the B/F cleaning liquid flows through the pipe 31 in theclogging determination time that is after the normal determination time.Thus, the cleaning device 20 determines that the suction nozzle 21 b isclogged (Step S120). Therefore, the cleaning device 20 stops dischargingthe B/F cleaning liquid to the reaction vessel 7 a (Step S122), andterminates the clogging detection of the suction nozzle 21 b. Thecleaning device 20 then causes the output unit 43 of the automaticanalyzer 1 to display a warning such as the effect that the suctionnozzle 21 b is clogged or the requirement of maintenance.

When the cleaning operation of the suction nozzle 21 b in the cleaningtank 30 is terminated, the nozzle transferring unit 22 of the cleaningdevice 20 returns the plurality of B/F cleaning nozzle pairs 21A to 21Fto the position of the reaction vessel 7 a of the reaction table 7 tostart sucking the reaction liquid within the reaction vessel 7 a. If theB/F cleaning liquid is discharged to the reaction vessel 7 a when thesuction nozzle 21 b is clogged, the suction nozzle 21 b cannot suck thereaction liquid within the reaction vessel 7 a and thus the B/F cleaningliquid overflows from the reaction vessel 7 a. Therefore, the cleaningdevice 20 stops discharging the B/F cleaning liquid to the reactionvessel 7 a.

As described, the cleaning device 20 detects the change of electrostaticcapacity between the suction nozzle 21 b and the reservoir electrode 33a as a binarized waveform that is the difference relative to a thresholdvoltage, and determines whether the suction nozzle 21 b is clogged basedon the totalizing times T1 and T2 of the binarized waveform in thenormal determination time and the clogging determination time. Thereaction liquid sucked by the suction nozzle 21 b during B/F cleaninghas a large fluctuation range of an electrostatic capacity, whereas theB/F cleaning liquid is stable because of a small fluctuation range of anelectrostatic capacity. Thus, it is preferable to use the B/F cleaningliquid in terms of the detection precision of electrostatic capacity orthe accuracy of detection.

The cleaning device 20 detects whether the suction nozzle 21 b isclogged based on the change of electrostatic capacity caused by the B/Fcleaning liquid flowing through the pipe 31 between the suction nozzle21 b and the reservoir electrode 33 a of the reservoir 33. The cleaningdevice 20 may alternatively detect whether the suction nozzle 21 b isclogged based on the change of electrostatic capacity caused by the B/Fcleaning liquid flowing through at least one of the pipe 31 between thesuction nozzle 21 b and the detection electrode 32 and the pipe 31between the detection electrode 32 and the reservoir electrode 33 a ofthe reservoir 33.

FIG. 14 illustrates examples of the voltage variation, the thresholdvoltage, and the binarized waveform output from the differentialamplifier 36 j of the detecting unit 36 based on the change ofelectrostatic capacity caused by the B/F cleaning liquid flowing throughthe pipe 31 between the suction nozzle 21 b and the detection electrode32 when the suction nozzle 21 b is not clogged with foreign materials.FIG. 14 also indicates the normal determination time and the cloggingdetermination time.

In contrast, FIG. 15 illustrates examples of the voltage variation, thethreshold voltage, and the binarized waveform output from thedifferential amplifier 36 j of the detecting unit 36 in the normaldetermination time and the clogging determination time when the suctionnozzle 21 b is partially clogged. When the suction nozzle 21 b isperfectly clogged, the voltage variation, the threshold voltage, and thebinarized waveform output from the differential amplifier 36 j of thedetecting unit 36 in the normal determination time and the cloggingdetermination time are as illustrated FIG. 12.

The cleaning device 20 can determine whether the suction nozzle 21 b isclogged by comparing the totalizing time T1 of the binarized waveform inthe normal determination time with the totalizing time T2 of thebinarized waveform in the clogging determination time that arecalculated based on the change of electrostatic capacity between thesuction nozzle 21 b and the detection electrode 32. Similarly, thecleaning device 20 can detect whether the suction nozzle 21 b is cloggedbased on the change of electrostatic capacity between the detectionelectrode 32 and the reservoir electrode 33 a of the reservoir 33.

It is preferable that the cleaning device 20 detects whether the suctionnozzle 21 b is clogged based on the change of electrostatic capacitybetween the suction nozzle 21 b and the reservoir electrode 33 a of thereservoir 33 because the flow of the B/F cleaning liquid can be checkedover the entire length of the pipe 31. However, it is advantageous thatthe cleaning device 20 detects whether the suction nozzle 21 b isclogged based on the change of electrostatic capacity between thesuction nozzle 21 b and the detection electrode 32 because the cloggingof the suction nozzle 21 b can be quickly detected.

The cleaning device 20 can detect whether the suction nozzle 21 b isclogged, using the time at which the binarized waveform becomes an ONstate in the normal determination time illustrated in FIG. 10 as astandard and measuring the delay of the binarized waveform that is thetime difference (ΔT) illustrated in FIG. 11 between the time and thetime at which the binarized waveform becomes an ON state in the cloggingdetermination time by the first timer 39 e and the second timer 39 f. Inthis case, the occurrence of temporal clogging of the suction nozzle 21b and the pipe 31 can be known using the length of the measured timedifference (ΔT). If a relationship between the time at which thebinarized waveform becomes an ON state in the determination time and thetemporal clogging state of the suction nozzle 21 b and the pipe 31 ispreviously checked and is recorded in the storage unit 44, the automaticanalyzer 1 can automatically and previously notice the requirement ofmaintenance related to the B/F cleaning nozzle pairs 21A to 21F and thepipe 31 using the control unit 45.

In the cleaning period illustrated in FIG. 5, the transfer time and stoptime of the B/F cleaning nozzle pairs performed by the nozzletransferring unit 22, the discharge time of the B/F cleaning liquidperformed by the discharge nozzle 21 a, and the opening time of thesuction valve 34 and the opening time of the exhaust valve 35 can beappropriately changed in accordance with the B/F cleaning situation inthe reaction vessel 7 a and the cleaning situation of the suction nozzle21 b in the cleaning tank 30.

In the embodiment, only the normal determination time and cloggingdetermination time are set. However, a gray zone time may be providedbetween the normal determination time and the clogging determinationtime so as to previously notice the maintenance of the B/F cleaningnozzle pairs 21A to 21F and the pipe 31.

In the above embodiment, the cleaning device, the method for detectingsuction nozzle clogging, and the automatic analyzer that are used for animmunological test are described. However, the present invention can beused in the cleaning device, the method for detecting suction nozzleclogging, and the automatic analyzer that are used for a biochemicaltest or a gene test.

The configuration of the detecting unit 36 is not limited to thatillustrated in FIG. 3 as far as it can detect the change ofelectrostatic capacity between the suction nozzle 21 b and the reservoirelectrode 33 a as a binarized waveform that is the difference relativeto a threshold voltage. Furthermore, the configuration of thedetermination control unit 37 is not limited to that illustrated in FIG.4 as far as it includes the peak-hold-reset output circuit 38 thatoutputs a peak-hold reset signal to the peak-hold circuit 36 i of thedetecting unit 36 and the determination unit 39 that determines whethereach of the suction nozzles 21 b is clogged based on the binarizedwaveform input from the detecting unit 36.

Additional advantages and modifications will readily occur to thoseskilled in the art. Therefore, the invention in its broader aspects isnot limited to the specific details and representative embodiments shownand described herein. Accordingly, various modifications may be madewithout departing from the spirit or scope of the general inventiveconcept as defined by the appended claims and their equivalents.

What is claimed is:
 1. A clog detection device for an analyzercomprising: a suction nozzle, having a nozzle electrode associatedtherewith, that is configured for sucking liquid in a vessel; a pipeconnecting the suction nozzle to a discard vessel; a first electrodecoupled to the pipe; a second electrode coupled to the pipe and disposedin between the nozzle electrode and the first electrode; a detectingunit coupled to the suction nozzle, the first electrode, and the secondelectrode, wherein the detecting unit is programmed to (i) detect anoutput signal between first electrode and the second electrode, betweenthe suction nozzle and the second electrode, or between the suctionnozzle and the first electrode; (ii) compare the output signal to athreshold value; and (iii) output the difference between the outputsignal and the threshold value over time to a determination unit coupledto the detecting unit; and the determination unit, wherein thedetermination unit is programmed to (i) set a preset normaldetermination time and a preset clogging determination time; and (ii)determine that the suction nozzle is clogged when a totalizing time, forwhich the output signal exceeds the threshold value during the presetclogging determination time, is longer than a totalizing time, for whichthe output signal exceeds the threshold value during the preset normaldetermination time.
 2. The clog detection device of claim 1, wherein thesuction nozzle is made of electroconductive material and wherein thenozzle electrode is integral therewith.
 3. The clog detection device ofclaim 1, wherein the detecting unit is programmed to set the thresholdvalue as a voltage value.
 4. The clog detection device of claim 1,wherein the detecting unit is programmed to output the differencebetween the output signal and the threshold value over time in awaveform.
 5. The clog detection device of claim 1, wherein thedetermination unit is programmed to determine that the nozzle is cloggedwhen the totalizing time, for which the output signal exceeds thethreshold value during the preset clogging determination time, equalsthe totalizing time, for which the signal value exceeds the thresholdvalue during the preset normal determination time.
 6. The clog detectiondevice of claim 1, further comprising a discharge nozzle coupled to acleaning liquid vessel storing cleaning liquid via a pump thatdischarges a cleaning liquid.
 7. The clog detection device of claim 1,further comprising a discard vessel that is connected to the pipe todiscard the liquid.
 8. The clog detection device of claim 7, wherein thefirst electrode is coupled to the discard vessel via the pipe.
 9. Theclog detection device of claim 6, wherein the analyzer further comprisesa control unit coupled to the determination unit and the pump, whereinthe control unit is programmed to stop the discharge nozzle fromdischarging cleaning liquid when the determination unit determines thatthe suction nozzle is clogged.
 10. The clog detection device of claim 1,further comprising a storage unit, wherein the storage unit storesinformation including the normal determination time and the cloggingdetermination time.
 11. The clog detection device of claim 1, furthercomprising a vacuum pump, wherein the suction nozzle is coupled to thevacuum pump.
 12. The clog detection device of claim 1, wherein thedetecting unit is programmed to detect that the output signal variesaccording to the flow of the liquid in the pipe.
 13. An automaticanalyzer comprising a vessel, a stirring unit configured to stir aspecimen and a reagent in the vessel to cause a reaction, a photometryunit configured for measuring an optical characteristic of reactionliquid in the vessel, a control analysis system configured to analyzethe reaction liquid in the vessel, and the clog detection device ofclaim 1, wherein the suction nozzle is configured for sucking liquidfrom the vessel.
 14. The automatic analyzer of claim 13, wherein thestirring unit is configured to stir reagent comprising a solid phasecoupled to an antibody.
 15. The automatic analyzer of claim 14, whereinthe stirring unit is configured to stir a specimen component that bindsthe antibody in the reaction vessel.
 16. The automatic analyzer of claim13, wherein the stirring unit is configured to stir reagent comprising asolid phase coupled to an antigen that binds an antibody in thespecimen.
 17. An analyzer with a clog detection device, the clogdetection device comprising: a suction nozzle made of electro-conductivematerial configured for sucking liquid in a vessel; a pipe connectingthe suction nozzle to a discharge vessel; a first electrode coupled tothe pipe; a second electrode coupled to the pipe and disposed in betweenthe suction nozzle and the first electrode; a detecting unit coupled tothe suction nozzle, the first electrode, and the second electrode,wherein the detecting unit is programmed to (i) detect an output signalbetween the first electrode and the second electrode, between thesuction nozzle and the second electrode, or between the suction nozzleand the first electrode; (ii) compare the output signal to a thresholdvalue; and (iii) output the difference between the output signal and thethreshold value over time to a determination unit coupled to thedetecting unit; and the determination unit, wherein the determinationunit is programmed to (i) set a preset normal determination time and apreset clogging determination time; and (ii) determine that the suctionnozzle is clogged when a totalizing time, for which the output signalexceeds the threshold value during the preset clogging determinationtime, is longer than a totalizing time, for which the output signalexceeds the threshold value during the preset normal determination time.18. The analyzer of claim 17, wherein the detecting unit is programmedto output the difference between the output signal and the thresholdvalue over time in a waveform.
 19. The analyzer of claim 17, wherein theclog detection device is part of a cleaning device of an immunoassayanalyzer, and wherein the cleaning device is configured to removematerial not coupled to a solid phase.
 20. The clog detection device ofclaim 1, wherein the detecting unit is programmed to detect the outputsignal corresponding to change of electrostatic capacitance between thefirst electrode and second electrode, between the suction nozzle and thesecond electrode, or between the suction nozzle and the first electrode.